The present invention relates to an ink cartridge and its manufacturing method. Particularly, the invention relates to an ink cartridge which supplies ink to an ink jet recording apparatus through an ink supply needle of the ink jet recording apparatus.
There is an ink jet recording apparatus in which an ink cartridge is detachably mounted onto a carriage having an ink jet recording head thereby to supply ink. As an example of this ink cartridge, there is an ink cartridge having an outline of an approximately rectangular parallelepiped, in which a porous member including ink therein is housed. In this ink cartridge, since the ink is held into the ink cartridge, negative pressure is generated inside the ink cartridge.
This type of ink cartridge is made up of a container body having a shape of an approximately rectangular parallelepiped and the opened upper surface. The container body is provided, at its bottom surface, with an ink supply passage into which an ink supply needle of the ink jet recording apparatus is inserted. The porous member is inserted into the container body from the upper surface, and the upper surface is sealed by a lid member, whereby the ink cartridge is manufactured.
The porous member is inserted into the container body from the upper surface in order to press a portion of the porous member near the ink supply passage against the ink supply passage and the ink supply surface thereby to compress this portion of the porous member. The higher the density of the porous member becomes due to compression, the stronger its capillary power becomes, so that the compressed porous member can collect ink. Therefore, in order to decrease a shortage of ink supply, the above manufacturing method is used so that ink can be collected to the portion of the porous member near the ink supply surface.
However, in an On-carriage type of ink jet recording apparatus in which an ink cartridge is mounted onto a movable carriage having an ink recording head, in order to mount as many ink cartridges as possible on the carriage, there is a tendency to reduce the width of the ink cartridge in the scanning direction of the carriage. Particularly, a color ink jet recording apparatus can mount ink cartridges holding ink of four or more colors in order to improve color reproduction. In this case, it is desirable that the width of the ink cartridge in the carriage moving direction is made as small as possible in order to make the width of the recording apparatus small and further the height of each ink cartridge is several times as large as the width thereof in order to secure the enough ink capacity.
For the ink cartridge that is thus high and narrow, it is difficult to insert the porous member into the container from the upper surface of the container. Namely, the porous member has compressibility, and it is not easy to insert such the porous member into the narrow and long space where friction is large.
Therefore, an object of the invention is to provide an ink cartridge which can solve the above problem and its manufacturing method.
Further, the above ink cartridge of which the height is larger than the width thereof is weak in mechanical strength in the width direction. Namely, in the side surface of the ink cartridge, its surrounding portion is only connected to other surfaces. Therefore, regarding the side surface having the large height and large area, its central portion is not supported by any members. Consequently, in case that pressure reduction is performed by letting air out of the inside of the ink cartridge in order to make the inside of the ink cartridge in a negative pressure state, the side surface having this large area is easy to deform. In case that this deformation exceeds an allowable size of the cartridge, there is fear that the ink cartridge is broken. Further, in case that the user or the like holds the central portions of the side surfaces of the ink cartridge opposed to each other so as to pinch them, that is, in case that the strong power is applied to these portions, there is fear that the ink cartridge is broken.
Therefore, it is another object of the invention to provide an ink cartridge which can solve the above problem.